1. Field of the Invention
The present invention relates to a manually operated trigger type dispenser which is connected to the mouth of a container and sucks liquid from the container into a cylinder, compresses it and causes it to flow out by reciprocation of a piston in cooperation with a trigger.
2. Description of the Prior Art
The problem of destroying the ozone layer is now a great problem. Hence, dispensers which use no freon gas to pressurize liquid and which is rather manually operated to pressurize and force out liquid, are drawing more and more attention. In the dispenser of this kind, a dispenser body is connected by a bottle cap, for example, to the mouth of a container which holds liquid to be dispensed and cylinder is integrally formed on the dispenser body, for example.
A trigger pivotally connected to the dispenser, for example, and a piston reciprocates in the cylinder in cooperation with traction of the trigger against urging force of a return spring. When the piston is returned from the pushed-in position to the initial position, the interior of the cylinder is negatively pressurized. Then, a primary valve is opened and a secondary valve is closed. When the trigger is released, it is returned to its initial position by the urging force of the return spring and the piston is also returned to its inital position in cooperation with the trigger. Under the negative pressure in the cylinder, the liquid is sucked from the container into the cylinder through a suction tube and the primary valve as the liquid excludes residual air in the cylinder. Upon pulling the trigger against the return spring, the piston is pushed into the cylinder to pressurize the liquid in the cylinder. The pressurized liquid opens the secondary valve and flows out of the cylinder.
The liquid pressurized by the pump action of the piston in cooperation with the trigger flows into the flowing-out passage through the cylinder and the secondary valve. A blind-ended nozzle cap formed separately from the dispenser body is conncted to the front end of the dispenser body and a spinner (or a swirling member) is housed in the nozzle cap. The pressurized liquid is swirled by the spinner and flow-out of an orifice (or a flow-out port) formed on the front surface of the nozzle cap.
In the dispenser of this kind, the nozzle cap is threadably connected to the flowing-out passage of the dispenser body, and the state of liquid flow or a liquid flow pattern is changed by adjusting the distance between the spinner and the orifice by rotation the nozzle cap. When, however, the nozzle cap is rotated excessively in the dispenser having this structure, the nozzle cap may be disengaged from the dispenser body and may be lost. Further, since the liquid flow patterns continuously change, it is difficult to show the relation between the liquid flow patterns and the angles of rotation clearly.
In order to solve this problem, there has been proposed a manually operated trigger type dispenser which includes a spinner assembly fixed to the front end of the flowing-out passage of a dispenser body and a plurality of liquid flow controlling portions is formed in the spinner assembly and a nozzle cap is not threadably connected to the spinner assembly but is merely rotatably provided on it. For example, four liquid flow controlling portions are provided in the spinner assembly, for example, as disclosed in Japanese Examined Patent Application Publication No. 54-035681. Four marks, "High-Spray" at which completely sprayed flow is produced, "Low-Spray" at which not completely sprayed flow is produced, "Jet-Stream" at which not swirled, straight jet stream is produced and "Off" at which the orifice of the nozzle is disconnected from the flowing-out passage of the dispenser body are indicated on the nozzle cap at angular intervales of 90.degree.. When the mark corresponding to the required liquid flow pattern is shown on the upper surface of the nozzle cap by rotating it, the pressurized liquid flows out in the required flow pattern. At the "Off" mark, the nozzle is set to the not flowing-out position.
Since the nozzle cap is not threadably connected although it is rotatably provided in this structure, the nozzle cap is neither disengaged nor lost. The flow patterns are changed every time the nozzle cap is rotated through 90.degree.. Thus, the change-over of the flow patterns is ensured and the flow patterns can be noticed clearly at a glance of the mark showing the corresponding flow pattern.
When the use of the manually operated trigger type dispenser is interrupted, the liquid is sucked up into the cylinder, fills it and is retained in it. When the trigger is pulled again, even a child such as a baby can pull the trigger because the traction force of the trigger is not set to a large value. If the dispenser is put carelessly at a position which the child is accessible, the child may rotate the nozzle cap to cause the orifice to communicate with the flow-out passage and then may pull the trigger by mistake. The liquid which has flowed out may enter an eye or eyes of the child or may adhere to his or her skin, and an unexpected trouble may occur.
A manually operated trigger type dispenser is provided with a accident preventing safety mechanism called a child proof mechanism in order to prevent the trouble of this kind. In general, as child proof mechanisms are classified into two types, one which a holing piece of a trigger is provided on a dispenser body and engages an engaging hole formed in the trigger so as to forcibly prevent swinging of the trigger (for example, as disclosed in the U.S. Pat. Nos. 4,558,821 (Tada) and 3,927,834 (Tada). In the child proof mechanism of a trigger lock type, the holding piece is relatively large. When the dispenser is in use, the holding piece is not fixed but is released, and hinders traction of the trigger adversely. Further, the relatively large holding piece gives strange impression and deteriorates its appearance.